In a conventional image sensor package, a sensor chip is mounted on a chip carrier and is electrically connected to the chip carrier via bonding wires, and a piece of glass is provided above the sensor chip to allow an image to be captured by the sensor chip. The image sensor package can be integrated to an external device such as a printed circuit board (PCB) to be used in various electronic products such as digital still camera (DSC), digital video camera (DVC), optical mouse, cellular phone, fingerprint scanner, and so on.
Along with expansion of data transmission capacity and development of miniaturized and portable electronic products, integrated circuit (IC) packages have been developed to have an advanced chip-scale packaged (CSP) structure in response to the requirements such as plenty input/output (I/O) connections, high heat dissipating efficiency and size miniaturization for integrated circuits. Therefore, a chip-scale packaged sensor semiconductor device is provided to effectively reduce a size of the conventional image sensor package, wherein the semiconductor device is merely slightly larger in size than a sensor chip incorporated therein and thus can be effectively applied to miniaturized electronic products.
FIG. 1 (PRIOR ART) shows a chip-scale packaged sensor semiconductor device disclosed by U.S. Pat. No. 6,646,289. As shown in FIG. 1 (PRIOR ART), during fabrication of a wafer comprising sensor chips 11, a piece of glass 12 is applied over an active surface of the wafer to protect sensor regions 18 of the sensor chips 11, and an epoxy layer 13 and a protective layer 14 are applied over a non-active surface of the wafer. An etching process is performed on the non-active surface of the wafer to form a plurality of inclined slots 15, such that electrode pads 110 of the sensor chips 111 are exposed, and patterned circuit layers 16 are formed on side walls of the inclined slots 15 and extended to a bottom surface of the protective layer 14, allowing the circuit layers 16 to be electrically connected to the electrode pads 110 of the sensor chips 11. A plurality of solder balls 17 can subsequently be implanted on the circuit layers 16 at the bottom surface of the protective layer 14, and a singulation process is performed to form individual chip-scale packaged sensor semiconductor devices, such that the sensor semiconductor devices can directly be electrically connected to an external device by the solder balls 17.
However, in the foregoing sensor semiconductor device, since the circuit layers formed on the side walls of the inclined slots have an acute angle relative to the electrode pads of the sensor chip electrically connected to the circuit layers, such acute-angle connection positions between the circuit layers and the electrode pads may easily be subject to stress concentration, thereby causing problems such as circuit cracking, failure in electrical connection, and so on. As fabrication of the foregoing sensor semiconductor device is directly performed on the wafer, which requires complicated fabrication processes and does not effectively solve a known good die (KGD) problem, making the fabrication costs greatly increased.
Therefore, the problem to be solved herein is to provide a chip-scale sensor semiconductor device and a method for fabricating the same, whereby the sensor semiconductor device can be cost-effectively fabricated and a circuit-cracking problem is avoided.